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B4 – analyse the structure and function of biological molecules in living systems - carbohydratesKnow formulas, chemical structureList functionsDifferentiate between monosaccharaides,
disaccharides and polysaccharidesCompare structure of cellulose, starch and
glycogenExplain dehydration synthesis and
hydrolysis
Carbohydrates contain C, H, and O in a ratio of approximately 1:2:1
2:1 ratio of H to O is the same is in H2O Contain repetitions of H-C-OH
Monosaccharides (Simple carbohydrates, or sugars)
Common monosaccharides have 5 or 6 carbons, usually arranged in a ring
Hexoses are 6-carbon monosaccharides Ex. Glucose, fructose, and galactose
All have the formula C6H12O6
Differ in arrangement of atoms
Structural formula for glucose:
Each corner is a carbon atom
Pentoses are 5-Carbon monosaccharides Ex. Ribose
Monosaccharides combine in chains to form polymers
Two monosaccharides combined = a disaccharide
Several monosaccharides combined = a polysaccharide
Disaccharides (2 monosaccharides) Ex. glucose + glucose maltose
Glucose + fructose sucrose
Glucose + galactose lactose
Tastes like sugar, looks like sugar, but it’s not!
Polysaccharides (complex carbohydrates)
Long, branched or unbranched chains of monosaccharides (up to 4000!)
Common examples: starch, glycogen, cellulose
Differ in orientation of bonds and degree of branching
Starch
Glycogen
Cellulose
Glucose and other monosaccharides are used in cellular respiration, to provide energy for cellular functions in all living organisms
Glycogen is used for energy storage in animals (found mainly in muscles and liver)
Starch is used for energy storage in plants (digested by animals to provide energy from food)
Cellulose provides structure in plant cell walls
Monosaccharides combine to form polymers by the process of condensation synthesis, or dehydration synthesis
A water molecule is given off for each bond that forms
Polysaccharides are broken down into monosaccharides by the process of hydrolysis
One molecule of H2O is added for each bond that is broken